“You are a one-man army,” promises the slogan for Sega’s adaptation of Marvel and Paramount’s “Iron Man” movie. The problem is one-man armies need something to do besides fly through generic environments fighting hordes of generic enemies. “Iron Man” mars its solid technology and smooth controls with consistently awful level design, resulting in yet another mediocre movie-based game whose only hope for sales will come with the pic’s heavily hyped opening weekend.

Electronic Arts’ 2006 adaptation of “Superman Returns” was widely panned for featuring a hero with awesome powers and nothing fun to do. Sega seems to have failed to learn from EA’s mistakes, however, as it repeats them in “Iron Man.” At first, players will love getting their hands on the titular hero’s super-powered suit. Intuitive controls make weaving through the air, shooting three different weapons or ripping the top off a tank the kind of vicarious thrill that videogames do best.

After they get used to Iron Man’s abilities, however, players are faced with missions that will bore them to pieces when they’re not causing fits due to wild swings in difficulty. Destroying Tony Stark’s “weapons cache” that’s being used for nefarious purposes, for instance, involves flying around a bland desert valley in search of gray boxes that would never stand out as a “weapons cache” if they weren’t highlighted in bright orange.

Along the way, Iron Man has to take out a seemingly never-ending army of tanks, artillery and choppers. On their own, these enemies are tedious and repetitive, but when they combine, the game becomes overwhelming, with so many missiles and bullets coming at Iron Man simultaneously that it’s tough to do anything besides fire blindly and hope not to die, since that can trigger as much as 15 minutes of replaying.

Iron Man himself is sharply designed, but there’s little detail in the enemies, even the end-of-level bosses. Cut-scenes that unimaginatively copy the movie’s storyline are just as weak. Downey does a decent job with original voiceovers, but Stark has such a small library of lame quips that his voice quickly becomes as dull as the rest of the game.

Iron Man

Rated T. $30-$60

Production

A Sega presentation of a game developed by Secret Level and licensed by Marvel for the PC, Playstation 2, Playstation 3, Wii and Xbox 360. Reviewed on Xbox 360.